Field of the Invention
The present invention relates generally to a guide device for knee replacement. More particularly, the present invention relates to a guide device for knee replacement, the guide device configured such that during knee replacement surgery and/or knee replacement revision surgery for implanting a prosthetic knee implant, a degree of external rotation of a femur is identified and aligned through a cut surface of a proximal tibia, then a distance of a gap between the cut surface of the proximal tibia and a cut surface of a distal femur is identified during the surgery, so the degree of external rotation and the distance of the gap are identified simultaneously with one guide device, and thereby it is possible to facilitate the surgery, thereby reducing operation time and minimizing occurrence of a sequela of operation.
Description of the Related Art
Generally, when a knee joint is severely damaged by arthritis or injury, knee replacement surgery is performed to implant a knee implant instead of the damaged knee joint, which allows normal function of the knee. Further, after the knee replacement surgery, when problems, such as a pain, occur, knee replacement revision surgery is performed.
FIGS. 1 to 3 are reference views illustrating knee replacement; and FIG. 4 is a reference view illustrating a mechanical axis, a transepicondylar axis, and a posterior condylar axis.
Reference will be made to a conventional knee replacement surgery with reference to the accompanying drawings, hereinbelow.
Referring to FIGS. 1 to 4, a tibia 800 is coupled with a tibial component 910; a femur 830 is coupled with a femoral component 920; and a bearing 930 is disposed between the tibial component 910 and the femoral component 920. In order to implant the tibial component 910 and the femoral component 920 into the proximal tibia 810 and the distal femur 840, surgical sites are required to be formed in the proximal tibia 810 and the distal femur 840. To form cut surfaces 820 and 850 of the surgical sites, a standardized cutting guide is used. The cutting guide is a surgical tool for guiding to form the first cut surface 820 of the proximal tibia 810 and the second cut surface 850 of the distal femur 840 by putting the cutting guide on a front surface of the tibia 800 and/or the femur 830 and then inserting a cutting tool into a slit.
Here, the cut surfaces 820 and 850 should be formed to be perpendicular to a mechanical axis M of the tibia in order to allow normal walking after implanting an implant 900 into the knee. Accordingly, as each cutting guide 940, for example, a chamfer cutting guide, which is used to form a bore for allowing the femoral component 920 and the femur 830 to be securely coupled to each other by inserting a stem mounted on a rear surface of the femoral component 920 into the bore, and a box cutting guide, which is used to form the second cut surface 850 perpendicular to the mechanical axis M on the distal femur 840, whenever the chamfer cutting guide and the box cutting guide are put on a front surface of the femur 830, a guide device is required to precisely form the second cut surface 850 and the bore.
The mechanical axis M is an axis of the lower limb, and is perpendicular to both the transepicondylar axis T and the second cut surface 850. Further, the transepicondylar axis T is in parallel to the second cut surface 850, and subtends an angle of 3° with a posterior condylar axis P formed in the posterior condyle, which is a general indicator in the field of orthopedics, so the detailed description thereof will be omitted.
However, when knee replacement surgery and/or knee replacement revision surgery is performed, the transepicondylar axis T may not be identified because of a bone defect of the femur 830. Here, it may be difficult to identify an axis forming the second cut surface 850 through a conventional method of identifying the transepicondylar axis T. Accordingly, a criterion for allowing the degree of external rotation of the femur 830 to be identified is lost, and thus it is impossible to implant the implant 900 by aligning the external rotation.
Further, when knee replacement surgery and/or knee replacement revision surgery is performed, for contact force of the tibial component 910 and the femoral component 920, it is necessary to determine a thickness of the implant 900 to be implanted by identifying the distance of the gap G formed between the first cut surface 820 and the second cut surface 850 during surgery.
However, in the conventional method, when knee replacement surgery and/or knee replacement revision surgery is performed, a step of identifying the degree of external rotation of the femur 830, and another step of identifying the distance of the gap G are generally implemented by using different guide devices, and thus, the process of the surgery becomes complex and difficult. Accordingly, operation time may be long and a sequela of operation may occur.
Korean Patent No. 10-1515144 discloses “Patient specific surgical instrument with cutting guide”, which relates generally to a customized surgical instrument used to form a surgical site in the femur or the tibia for allowing the implant to be implanted thereinto, and more specifically, relates to a customized surgical instrument with a cutting guide, the surgical instrument including: a body surrounding a portion of a bone by being connected to the bone; and a cutting guide for guiding a cutting tool that is inserted into the body to form a cut surface of the bone, wherein the body includes a cutting guide insertion part provided at a side of the body, with an insertion hole penetrating through the cutting guide insertion part for allowing the cutting guide to be inserted thereinto; and the cutting guide includes a locking part locked to the body, a guide slot for allowing the cutting tool to be inserted thereinto, and an insertion part inserted into the insertion hole with a predetermined clearance, and thereby it is possible to adjust a location of the cutting guide.
However, even if the above surgical instrument is used, it is impossible to identify the cut surface of the tibia, the cut surface of the femur, and the degree of external rotation of the femur simultaneously with one disclosed surgical instrument, and thus the above described problems may occur.
Thus, a method of implementing a step of identifying the degree of external rotation of the femur 830, and another step of identifying the distance of the gap G, by using one guide device is required in order to reduce operation time through a simple surgical process.
The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.